barcode scanner code in PRINTED CIRCUITS HANDBOOK in Software


Decode Quick Response Code In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Paint QR Code In None
Using Barcode creation for Software Control to generate, create QR image in Software applications.
Axial leaded components are inserted before radial leaded components because, typically, axial components are smaller overall than radial components. Because the associated tooling size is also smaller, inserting axial components prior to the radial components facilitates the stuffing of higher-density circuit boards. Radial Leaded Components. After DIP and axial leaded components, the radial components are inserted into the circuit board. Radial components can vary greatly in size, shape, height, and weight (see Fig. 40.5). The lead finishes types and thicknesses are identical to those of axial leaded components. The possible exceptions are hermetically sealed components, such as active Si chip devices in TO-5 cans, optoelectronic packages, and relays. Such devices typically have low-expansion, Fe-based alloy leads that allow for them to be sealed into the header with a glass-to-metal joint. Although some device manufacturers use a Sn-Pb or 100 percent Sn finish over an electroplated Ni (solderable) layer, other suppliers prefer an Au (protective) finish over the Ni (solderable) layer to provide adequate solderability. In such cases, the Au layer is removed by hot solder dipping in order to prevent Au embrittlement of the circuit board interconnection.
Read QR Code JIS X 0510 In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
QR Code Maker In C#.NET
Using Barcode maker for Visual Studio .NET Control to generate, create QR-Code image in .NET framework applications.
FIGURE 40.5 Radial leaded components: (a) individually; (b) in taped reels. (Courtesy of Sandia National Laboratories and Universal Instruments.)
QR Code JIS X 0510 Printer In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create QR image in ASP.NET applications.
Denso QR Bar Code Printer In Visual Studio .NET
Using Barcode generator for .NET Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
Radial leaded components are taped together at the leads. Radial insertion machines remove the components from the tape and insert them in sequence on to the printed circuit board using a shuttle system similar to that used for other components. The insertion machine tooling for radial components is designed to avoid previously inserted DIP and axial components. Odd-Form Components. The odd-form components are the last devices to be assembled on the circuit board. Odd-form components, by definition, are those packages that are not readily addressed by automated assembly because (a) they are used at insufficient volumes on the product to justify machine space or (b) they are of a geometry (shape or size) that lacks the customer demand to justify the machine manufacturer to provide off-the-shelf tooling for them. High-power applications often require a variety of odd-form components, including simply oversized DIP, axial leaded packages, or radial leaded packages. Also, odd-form components include transformers, switches, relays, and connectors. Several of these packages are shown in Fig. 40.6. Unusual package sizes and geometries are often accompanied by unusual lead configurations and materials. It is not uncommon to have Cu- and Ni-based alloy leads, or even leads made of refractory materials such as Mo and Ni.The leads may be round, square, or in the form of ribbons. Irrespective of the lead material or nontypical geometry (which must have the hole geometry addressed at the circuit board design step), it is always required that the leads have adequate solderability. Leads are typically plated with solderable layers (Cu or Ni) and
QR Code JIS X 0510 Generation In VB.NET
Using Barcode generation for .NET framework Control to generate, create QR Code 2d barcode image in .NET applications.
EAN13 Encoder In None
Using Barcode creation for Software Control to generate, create GS1 - 13 image in Software applications.
Encode Barcode In None
Using Barcode generator for Software Control to generate, create barcode image in Software applications.
Code-128 Encoder In None
Using Barcode creator for Software Control to generate, create ANSI/AIM Code 128 image in Software applications.
Shrouded Power Header D-Sub
UPCA Creator In None
Using Barcode creation for Software Control to generate, create UPC Symbol image in Software applications.
Drawing DataMatrix In None
Using Barcode encoder for Software Control to generate, create Data Matrix image in Software applications.
Battery Holder
Painting GTIN - 12 In None
Using Barcode drawer for Software Control to generate, create UPC E image in Software applications.
UCC.EAN - 128 Encoder In None
Using Barcode creation for Microsoft Excel Control to generate, create UCC-128 image in Excel applications.
Code 128 Code Set B Printer In VS .NET
Using Barcode printer for ASP.NET Control to generate, create Code 128 image in ASP.NET applications.
UPC Symbol Recognizer In Visual C#.NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in .NET applications.
ZIF Socket 7
Code 39 Extended Reader In VB.NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in .NET applications.
Data Matrix ECC200 Decoder In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
EAN13 Generation In Java
Using Barcode creation for Android Control to generate, create EAN13 image in Android applications.
Generate UPC - 13 In Java
Using Barcode maker for Eclipse BIRT Control to generate, create European Article Number 13 image in Eclipse BIRT applications.
Phone Jack DIMM Mini Din
Stacked D-Sub
Stacked DIN
Audio Jack
Slot 1 Connector
FIGURE 40.6 Examples of odd-form, through-hole components and a circuit board assembly. (Courtesy of Universal Instruments.)
protective finishes (Au, Sn, Sn-Pb, etc.) very much like those used on traditional components to support the soldering process. Insertion Equipment. Because the demand for through-hole circuit boards has remained strong, insertion equipment capabilities have steadily improved. Brushless servomotors and state-of-the-art motion controllers and sensors have replaced most pneumatic drive assemblies and bulky (and slow) mechanical switches and relays, respectively. Some equipment options include the capability to test parts electrically prior to insertion. At insertion rates of up to 40,000 components per hour (CPH), defect rates are a couple of hundred parts per million or lower for the common axial and radial leaded packages. Interchangeable tooling has allowed the automated insertion of many odd-form components, as well. The change to Pb-free solders does not have a direct impact on insertion equipment technology. 40.2.6 Automated Soldering and Wave Soldering The most commonly used process for the soldering of through-hole and mixed (through-hole and surface-mount) circuit boards is wave soldering. The wave-soldering process is shown schematically in Fig. 40.7. The populated (or stuffed ) circuit board is secured to a conveyor belt. The conveyor belt carries the board through the fluxer, then the preheat stage, and lastly on to the molten solder wave. Interestingly, one of the most critical steps in the wave-soldering process is the application of the flux. Manual fluxing has given way to more precise, automated equipment in order to improve yields. The advantage is better control of the quantity of flux on the circuit board as it enters the wave because the flux controls both the entry and exit geometries of the molten solder wave, which in turn are instrumental toward minimizing skips, bridges, or icicle defects. Flux can be applied by spraying techniques or by passing the circuit board through the foam or suds of the flux. The latter technique is provided by the foam fluxer.
Copyright © . All rights reserved.